IDIDIT - The short answer is that you can floppy boot your computer with any recent version of DOS (6.22/3.x/95/98/ME) and run the Maxtor diagnostic program. If you have the actual Maxtor disk, it should be bootable. If any (single) boot disk you created in XP as you described boots *directly* to the A prompt (no XP setup-type screens first) then that will work as well.
Don't worry about the fact that the hard drive had XP or used NTFS, or what partitions or RAID volumes ever existed on it - the Maxtor utility ignores all of this and does it's checking at the drive's hardware level writing directly to the disk sectors.
Background:
You're probably getting confused by the term 'startup' disk. An installed XP system does not have the capability to be 'started' from a DOS prompt in the usual sense, i.e., by typing WIN from a prompt. The seven floppies you downloaded were not intended to get you to a DOS A: prompt - they were intended to boot into the XP setup routine or (optionally) it's recovery environment.
Even if you opted for the XP 'repair' and got to what looked like a DOS prompt, you still wouldn't be able to run the Maxtor utility. There's only a limited set of internal commands for the most basic of XP file and system related functions. You could 'see' the utility .exe file (using DIR), move it or delete it, but not run it. It's not a shell for running external programs, and it's not what you want.
The disk you created in XP is a bare-bones MS-DOS boot disk (uses ME's command.com). It should have worked fine to at least get you to an A: prompt. Your BIOS, however, decides which order it's going to search through the bootable devices. It's probably set to look at the A: drive *after* checking for a bootable C: or RAID drive. It's erroring out before it can even look at the A: drive.
If you were successful at changing the boot sequence in your BIOS, you should be able to use it now for running the Maxtor utility. There *is* the possibility that the floppy itself is bad, but I suspect that you could take it to another machine and it would boot fine.
The "MS_DOS" boot disks (Win ME) that XP creates generally cannot be used to see any NTFS-formatted partitions. If you are trying to get at another hard drive on the machine to copy or run the Maxtor utility *and* the drive/partition was formatted as NTFS, the problem is a little more complex. It's much easier just to get the utility on any bootable floppy and run it from there.
Now there is a way to 'start' a working, hard-drive based copy of XP already loaded on your machine by booting from a special floppy, but I'm assuming this isn't your concern at this point.